The invention is based on a method for fuel injection in internal combustion engines, in particular diesel engines. The quantity of fuel to be injected is metered before the onset of the compression stroke, at a regulated, preferably constant fuel inflow pressure, by a controllable inflow cross section of an inflow valve. This inflow valve is inserted into an inflow line leading to the pump work chamber of a piston injection pump. The end of supply is fixed by means of the relief of the pump work chamber and thus by means of a controlled return-flow fuel quantity.
The invention is also based on a fuel injection apparatus for performing this method, which comprises a piston injection pump provided with an adjustment device for the correction of the end of the effective supply stroke. This adjustment device variably controls the relative position of a diversion opening and control face closing apparatus. A supply pump generates the necessary inflow pressure and is controlled by a regulating valve.
In a fuel injection pump known from German Examined Application DE-AS 1 143 674, the quantity of fuel to be injected is regulated, at a constant fuel inlet pressure, by means of the variable inlet cross section of an inlet valve which is embodied as a throttle element. The pump piston, which is provided with an oblique control edge in order to limit the effective supply stroke, is not, however, adjusted between idling and full load; instead, the oblique control edge fixes a termination of supply which always remains unchanged and a full-load quantity which is limited by the maximum possible fill level of the pump work chamber. The oblique control edge is capable solely of being adjusted in terms of its rotary position, in order to control an increased starting quantity. In this fuel injection pump, which is also known as an intake-throttle pump, the result is an injected onset which necessarily varies in accordance with the supply quantity; this injection onset can be corrected only via expensive injection adjusters, which are incorporated in the camshaft drive mechanism and transmit all the torque. It is the object of the invention to create a method for fuel injection, and apparatuses for performing this method, with which a change in supply onset which is either arbitrary or dependent on engine operating characteristics can be attained while retaining precise fuel-quantity metering avoiding the use of components which transmit drive torque.